The evolution of light-weight, easily erected and economical portable shelters has led to the increasing commercial and private use of these structures. Portable shelters typically employ a cloth or plastic material attached to a light-weight, highly foldable skeleton or frame structure. The cloth provides a roof and/or walls for the shelter, and the frame structure provides support for the cloth, for example, the frame structure includes legs to elevate the roof and a system of trusses to support the roof and to generally stabilize the shelter. The frame structure often incorporates a compound, scissor-like, arrangement of a light-weight, tubular material such as aluminum. In order to maximize the usable area under a shelter, the frame structure is often designed so that the roof is supported solely by legs positioned near the perimeter of the roof. Stated alternatively, shelters do not typically employ an interior supporting post or leg such as a leg or post positioned in the center of shelter. U.S. Pat. No. 4,641,676 to Lynch, U.S. Pat. No. 7,367,348 to Tsai, and, and U.S. Pub. No. 20120048319 to Dotterweich, the contents of which are herein incorporated by reference, are examples of such portable shelters.
Some prior art frame structures used simple pins, such as push-pin or pull pin mechanisms to releasably support a frame structure in its expanded configuration. While these mechanisms typically provide adequate support, the relatively heavy weight of the upper portions of the framework can make them difficult to push or pull when trying to fold up the structure. Additionally, these pins are typically located in close proximity to sliding members and therefore, when pressed/pulled, can result in pinching or damage to a user's hand.